The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Light emitting diodes (LED) have been popular in electronic device applications, for instance, indicator applications, displays of laboratory instruments, and illumination applications such as home, office, and outdoor lighting. An LED string that includes a plurality of LEDs connected to each other utilizes a current flowing thorough the LEDs for operation.
When an overshoot of the current flowing through the LEDs occurs, the overshoot may produce a brief interval during which light emitted from the LEDs is undesirably bright, such as by producing a flash of light. On the other hand, when the current flowing through the LEDs decreases at a rate greater than a certain value, the change may produce a flickering of light. The occurrence of such a flickering may also depend on a dimming level, a switching frequency in a pulse width modulation (PWM) control system, or the like.